Automotive vehicles are generally equipped with various restraint devices that deploy in the event that a vehicle is involved in a crash, such as a forward collision, a rear collision, a side (lateral) collision or a rollover. For example, air bags, side curtains, seatbelt pretensioners, pop-up roll bars and other devices can be deployed when certain crash events are detected. These and other restraint devices require timely deployment to mitigate adverse effects to occupants in the vehicle. To achieve timely deployment of restraint devices, the vehicle dynamics generally must be monitored and a decision must be made to determine whether some type of vehicle crash is anticipated to occur or is occurring.
Various vehicle crash sensing systems employ sensors to sense dynamic conditions of the vehicle. For example, a conventional crash sensing system may employ inertial sensors for sensing linear acceleration and/or angular velocity. Some conventional crash sensing systems are designed to detect only a frontal crash event. Other crash sensing systems have been designed to detect other vehicle crash events such as a side impact crash, a rear impact crash and vehicle rollover events.
Each type of crash event detection generally employs inertial sensing requirements that are unique to that type of crash event. These requirements generally place constraints on the range, resolution and placement within the vehicle of each type of inertial sensor. Consequently, increasing the types of crash events that can be detected for a vehicle necessarily increases the number of sensors that are generally required to detect those crash events, and thereby results in an increase in the cost of the overall crash detection systems. For example, a conventional vehicle side impact crash detection system may employ a single linear accelerometer, the output of which is processed by a side crash event algorithm. A separate and distinct rollover crash sensing system may employ another separate and distinct accelerometer along with an angular rate sensor, the outputs of which are processed by a rollover crash event algorithm. The two separate crash sensing systems typically employ separate inertial acceleration sensors that are each calibrated for a specific crash event and are not integrated.
It is therefore desirable to provide for a cost-effective vehicle crash sensing system that advantageously integrates device(s), and is capable of detecting multiple crash sensing events. In particular, it is desirable to provide for a vehicle crash sensing system that integrates one or more inertial sensors into one crash sensing system capable of detecting multiple crash events.